Numerical Simulation Of Buckling Mechanism On Dented Subsea Pipelines

There are always dents on the outside surface of pipelines during the installation and service period. And it is much easier to come into buckling under the external loads for subsea pipelines. So it has great significance to develop the research on buckling mechanism of dented subsea pipelines.Based on the nonlinear numerical simulation with ABAQUS, this paper developed the research and analysis on buckling mechanism under external pressure and bending moment with the study object of sphere and ellipse dented subsea pipelines. The content and results are as follows:(1) Developed the complete finite element model for numerical simulation, and verified its accuracy through comparison with recent results. According to dimensions correlation analysis, simplified the models of sphere and ellipse indenter.(2) Made researches on buckling mechanism of sphere and ellipse dented subsea pipelines under pure external pressure and pure bending moment respectively. And the influence of dent depth, dent length and width ratio, diameter and thickness ratio for buckling process is presented. Meanwhile, the related fitting formulas used to calculate the critical value of buckling loads for dented subsea pipelines under pure external loads is proposed.(3) Different loading paths have different influences on buckling mechanism for dented subsea pipelines under combined external pressure and bending moment. The degree of deviation for buckling critical value under combined loads with the one unders pure load is presented.